An air handling system typically conditions a supply of air moving therethrough by heating, cooling or otherwise effecting the quality of the air moving through an air handling unit, such as an HVAC (heating, ventilation and/or air conditioning (cooling, humidifying, etc.)) unit. An air handling system typically includes a network of air ducts, and a supply duct and branches thereof generally deliver conditioned air from the air handling unit to a plurality of zones that make up the conditioned space. As the airflow to one or more zones changes, the airflow through the supply duct and its branches can become undesirably noisy, inefficient in mixing with the air in the conditioned space and/or have an objectionable feel to some occupants of the conditioned space in the path of the airflow.
One way to reduce or eliminate these problems is to divert some of the air from the supply duct through a bypass duct while maintaining a more consistent air pressure or air velocity in the supply duct. Many of the systems used to control the airflow through the bypass duct, however, are difficult to install and/or set properly, introduce other noises and/or are unstable.